This invention relates generally to radio transceiver units, and in particular, to interchangeable front control panel and keypad assemblies for such units.
For marketing and other reasons, manufacturers of radio communications devices typically offer several different configurations for each communications product manufactured. A particular model of mobile radio transceiver may have a "basic" or minimal configuration but may optionally be provided with additional features or "options" at additional cost.
For example, a basic transceiver configuration may provide communications over a limited number of communications channels for basic radio transmitting and receiving functions required by all users. Some users may, however, have additional requirements requiring additional features--such as additional communications channels, receiver channel scanning, etc. The ability of a manufacturer to provide such additional "options" permits increases in the flexibility, versatility, desirability and range of applications of the product without penalizing purchasers of the basic configuration with increased cost. Purchasers of the basic model pay a minimum price for the minimal configuration, while users requiring additional "option" features pay an increased price based on the number and type of options required.
In the past, additional options were generally provided by incorporating additional components and circuitry into the device. For example, in the past, channel scanning capability or additional operating channels were added by installing additional frequency selection circuitry into the transceiver. Similarly, the tone activated squelch option typically required an additional tone decoder circuit to be installed. Transceiver designers used modular architectures to accommodate additional plug-in "option modules".
An example of this design approach is the prior art "MLS" series radio transceivers manufactured for General Electric Company by Japan Radio Corp. These "MLS" transceivers include basic transceiver circuitry disposed within a housing. The front panel assembly of the transceiver housing was manufactured separately, and consists of a separable front panel "escutcheon" plate. Mechanically mounted to the escutcheon plate is a printed circuit board which plug-connects to the basic transceiver circuitry when the escutcheon plate is mechanically fastened to the housing. The escutcheon plate and associated printed circuit board comprises a module separable from the transceiver main housing and basic circuitry. The module includes user controls mounted on the escutcheon plate and circuitry required to connect user controls mounted on the plate to the transceiver circuitry.
Since different "option" features in many cases require different additional user controls, different models of escutcheon plate modules were produced for the "MLS" series transceivers. In particular, the "MLS" transceiver was made available in five different versions: (1) a two-channel "basic" version; (2) an 8-channel version with the scan feature; (3) a 16-channel version without scan; and (4) a 16-channel version with scan feature. Five different interchangeable escutcheon plates with different user control arrangements corresponding to these five different transceiver versions were also made. The particular escutcheon plate/control panel installed on a particular "MLS" transceiver limited the transceiver features the user could access. For example, the escutcheon plate corresponding to the "MLS" transceiver versions with 16-channel capability and no scan feature does not have a control to actuate the scan feature--preventing the user from obtaining the benefit of the scan feature. Similarly, the escutcheon plates corresponding to the 8-channel transceiver versions do not include user controls to access more than 8 channels.
Since all "MLS" transceivers included identical basic transceiver circuitry and main housing, reduced manufacturing costs and increased reliability derived from large scale manufacturing were obtained. Specific purchaser selected options could be provided in a particular unit simply by installing the appropriate escutcheon plate module --a procedure which could be performed in the field if desired. Incorporation of the circuitry performing the option functions and user controls interacting with such circuitry within the same front panel escutcheon plate module permitted a transceiver to be reconfigured by simply "unplugging" one module and "plugging in" a different module (further increasing reliability and decreasing manufacturing costs).
In this regard, see commonly assigned U.S. patent application Ser. No. 07/183,212 filed Apr. 19, 1988.
It is a principal object of this invention to provide a transceiver design which permits quick assembly of interchangeable front control panels and associated rubber keypads in order to convert an otherwise standard transceiver design to different versions of varying capabilities.
One advantage of the present invention is that a sixteen channel capacity unit, for example, can be configured as a four channel unit by installation of a four-key keypad and a four-key control panel, even though the unit has the capability of a sixteen channel unit. The final assembly of the control panel and keypad can be carried out easily and quickly at the point of distribution as required. As a result, otherwise standardized transceiver units can be configured quickly and simply, outside the manufacturing facility, so that unnecessary production delays need not be experienced while awaiting customer specifications.
Another advantageous aspect of the present invention lies in the fact that a standardized circuit including an array of switches, is enclosed within the housing, and that no circuitry or electrical components need be included in the keypad and/or control panel elements, with the exception of the conductive carbon buttons on the backside of respective keys of the keypad. This then permits conversion to various model designs merely by the utilization of low cost control panels and keypads, designed to selectively access some or all of the switch elements on the underlying circuit board.
It is another advantage of the present invention that the front control panel and keypad design flexibility allows future similar designs to be made quickly and cheaply to a standard product line transceiver.
In one exemplary embodiment of the invention, a relatively thin planar control panel defined by upper, lower and a pair of side edges, is provided with a projection, or locking bar, extending along and away from the upper edge of the panel. This projection is designed to be received in a recess provided within the transceiver unit housing. At the same time, a pair of apertures are provided adjacent the opposite or lower edge to receive a pair of screws to securely fasten the control panel to the front cover of the transceiver unit housing. A number of interchangeable control panels are provided, with different members and configurations of key apertures, depending on the desired end configuration for the unit.
In the exemplary embodiment, the locking bar extending upwardly and away from the upper edge of the control panel is centered between the side edges, but it will be appreciated that it may also extend along the entire length of the upper edge. The recess in which the locking bar is received is formed by a combination of the front cover of the unit housing, a display escutcheon plate located directly above the control panel, and the upper edge of the associated rubber keypad.
It is also a feature of the exemplary embodiment of the invention to provide a corresponding number of rubber keypads with identical peripheral shapes, but with different numbers of keys, again depending on the desired end configuration for the unit.
In order to fasten a selected control panel and corresponding keypad to the front cover of the unit, the keypad (preferably made of rubber or other suitable resilient material) is first placed in position within a recess provided in the front cover. The corresponding control panel is oriented such that the locking bar is slipped upwardly into the above described recess, and the panel is then pivoted downwardly and pressed into contact with the underlying keypad so that the screw holes provided in the control panel are aligned with corresponding screw holes in both the keypad and in the front cover of the housing. By merely inserting and tightening a pair of screws in these two screw holes, the front control panel cover is securely mounted to the housing, with the locking bar securely held underneath the display escutcheon plate. At the same time, the control panel cover captures the rubber keypad, pressing it down against the front housing cover to form a weatherproof seal.
It will be understood that the front control panel cover and associated keypad may be provided in a variety of configurations, for example they may be provided with sixteen holes to accommodate a sixteen-key keypad; four holes for accommodating a four-key keypad; a blank front control panel, i.e., one with no apertures for those applications where a blank keypad is employed, and so on. In converting the unit from one configuration to another, the electrical circuitry is not altered. What is altered is the degree of accessibility to the switch elements located within the unit.
Thus, in accordance with one aspect of the present invention, there is provided a control panel for a radio transceiver unit comprising a relatively thin, planar member having front and rear surfaces and defined by upper, lower and a pair of side edges; a projection extending along and away from at least one of the edges; and fastening means located adjacent an opposite edge.
In another aspect of the present invention, there is provided a radio transceiver comprising a housing having a front cover, a control panel mounted on the front cover, a keypad provided with a plurality of keys adapted to make electrical connection with a circuit located within the housing; and overlying the keypad, the control panel comprising a relatively thin, planar member having front and rear surfaces and defined by upper, lower and a pair of side edges; a plurality of apertures corresponding to and aligned with the plurality of keys; a locking bar extending along and away from one of the edges, and fastening means located adjacent an another edge, opposite to the one edge.
In still another aspect, the present invention comprises a housing including a front cover, an array of electrical switches located within the housing, a plurality of interchangeable control panels adapted for selective alternative attachment to the front cover, and a plurality of interchangeable keypads adapted for selective alternative attachment to the front cover in underlying relationship with a respective one of the control panels, wherein each control panel is configured for use with a similarly configured one of the keypads, and wherein said keypads are formed with different numbers of keys, respectively for accessing selected ones of the switches in said array.
In a related aspect, the present invention relates to a method of reconfiguring an otherwise standardized radio design comprising the steps of (a) providing a transceiver unit including a housing, the housing having a front cover adapted to receive a keypad and a control panel; (b) providing a circuit board within the housing, the circuit board including an array of switches; and (c) selecting a keypad and associated control panel which permits access to some or all of the switches, depending on the number of keys provided on the selected keypad.
As a result of the above described invention, different versions of otherwise standardized transceivers can be achieved quickly and simply through the utilization of the quick connect and disconnect front control panel covers as described herein. Additional objects and advantages of the present invention will become apparent from the detailed description of the invention which follows.